Firearm accessory mount adapted for use with rifles having tangent or ladder-style read sights

ABSTRACT

An accessory mount is removably affixed in place of a pre-existing tangent rear sight lever arm or leaf. The accessory mount is adapted for installation by a user without gunsmithing and includes an elongated body with a distal protuberance carrying opposing transverse trunnions or pins adapted to engage the tangent sight&#39;s base. In a preferred embodiment of the present invention, the elongated body has an upper surface configured to accept accessories designed to clamp on a Picatinny-style rail, or a Weaver™ style rail and so provides a universal mounting surface for optical sights, scope rings or other accessories.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority, under 35 U.S.C. 119(e), to U.S.Provisional Application No. 60/771,019 filed Feb. 8, 2006, the entirecontents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to firearms and accessory mounts forsecuring accessories, such as optical sights, to firearms.

2. Description of Related Art

Soviet and Eastern-Bloc firearm designs have become widely available tothe public, and purchasers of rifles often want to use optical sights orother firearm accessories that are not readily mounted on riflespatterned after those designs.

To name one example, the AK-47 (Avtomat Kalashnikova 1947) is agas-operated assault rifle designed by Mikhail Kalashnikov, produced byRussian manufacturers, and used in many Eastern bloc nations during theCold War. It was adopted and standardized in 1947. It was one of thefirst and surely the most prolific assault rifle. The AK-47 and numerousvariants, was produced in greater numbers than any other assault riflein the 20th century and continues in production to this day.

The AK's notched rear tangent iron sight has a pivoting lever arm thatis pinned at its forward or distal end. As issued, the sight's lever armis calibrated with each numeral denoting hundreds of meters. The frontsight is a post adjustable for elevation in the field. Windageadjustment is done by the armory prior to issue. The battle settingplaces the round within a few centimeters above or below the point ofaim out to approximately 250 meters. This “point-blank range” settingallows the shooter to fire the gun at any close target without adjustingthe sights. Longer settings are intended for area suppression. The AK'ssights were fashioned to emulate the Mosin-Nagant and SKS rifles whichthe AK-47 replaced in order to ease transition and simplify training.

The AK-47 is in the AK family of weapons, including the Chinese Norinco,or Poly Tech™, AKS, type 56, AK-47 S, the Hungarian AKM variations, theRomanian AKM variations, the AK-74, the Polish Tan Tal and the RussianAK 74 versions and the 545. Most often, three variations are discussed,including the AKS, AKM, and AK-74 and the pre-existing rear sightsupports differ only in minute details. Each has a rear sight thatincludes an adjustable tangent sight with a hinged member that is hingedat the distal or barrel end of the sight and is aligned along the bore.Typically a tangent sight has a sliding member that bears on left andright walls having curved surfaces.

The tangent sights on all of these rifles, while crudely effective, donot provide the precision now sought by many sportsmen who have recentlyacquired these rifles, and many users now seek a simple and effectiveway to mount telescopic sights and other types of optical sighting aids.Modern optical sights include the AimPoint™ and the EO-Tech™ red dotsights, and such sights do not work well when mounted upon an assaultstyle rifle's receiver.

Others have attempted to make aftermarket mounts available, but withlimited success. In general, the releasable mounts or replacementreceivers with attached scope mounts (e.g., a Weaver or picatinny rail)are not very stable and are not precise enough to guarantee that a thepoint of aim or “zero” will be restored once the user disassembles thefirearm for cleaning. At the end of the shooter's day, to clean the gunone must take the gun apart and there is no way to do that withoutremoving the receiver cover first, at which point the zero is lost,since upon re-installation, the point of aim will have changed. Theproblem with mounting either dovetails or mounting plates on the leftside of the AK receiver is that it alters the weapon permanently andtechnical issues often foil unskilled people trying to mount these typesof plates. One can mount the plate in the wrong place and actually blockinternal moving parts, interfering with the insertion of the magazine.Such changes also permanently destroy a rifle's collector value. Othersuse picatinny rails manufactured right into forearms to replace thestandard forearms and when mounting an optic there, the optic is too farforward to see a correct sight picture. The more serious problem,though, is that it gets very hot near the forearm very quickly, sincethe forearm is directly over the gas tube on an AK, and an unwary usercan overheat and damage an optical sight.

Another problem confronting the shooter on a limited budget is that theAK and its variants often were manufactured using stamped steelreceivers, and so were not suited to conventional scope rail mounts,which are usually affixed by threaded fasteners after drilling andtapping a rifle's receiver.

There is a need, therefore, for a method and apparatus for mountingtelescopic sights and other types of optical sighting aids andaccessories onto inexpensive surplus rifles such as the AK-47.

BRIEF SUMMARY OF THE INVENTION

Accordingly, the present invention overcomes the above mentioneddifficulties by providing an easily installed accessory mount for usewith rifles carrying tangent or ladder-style sights. Preferably, thepresent invention provides an accessory mount which permits attachmentof Picatinny rail compatible accessories onto older rifles havingstamped steel receivers or other impediments to use of conventionalmounts. These advantages may be achieved individually and incombination, and it is not intended that the present invention beconstrued as requiring two or more of these advantages to be combined.

The accessory mount of the present invention removably engages to mountsupon a rifle in a safe place located at a pre-existing tangent sightbase. In accordance with a preferred embodiment of the presentinvention, the accessory mount is adapted for installation by a userwithout requiring tools, alteration or gunsmithing and includes anelongated body with an upper surface configured to accept accessoriesdesigned to clamp on a Picatinny-style Rail, and so provides a universalmounting surface for optical sights. The accessory mount of the presentinvention has an elongated body with a distally projecting protuberancecarrying laterally opposing transverse pin members. In a preferredembodiment of the present invention, the overall length of the accessorymount is 105 mm or 4.134 inches and terminates proximally in a taperedend. In this preferred embodiment, for most of its length, the width ofthe accessory mount is 16.155 mm, and the mount has V-shaped opposinglateral edges adapted to receive clamping attachments used with eitherpicatinny or Weaver™ style mounts. It should be understood that theexact dimensions of the accessory mount may vary.

This removable accessory mount doesn't interfere with the function ofthe rifle in any way. The place on the rifle where the accessory mountis attached does not get too hot and it is easy to disassemble since allthat one must do is fold or raise it slightly upward. The accessorymount may be locked by tilting it up and forward where it can also befreed and stripped from the receiver's tangent sight base sidewalls.Since the accessory mount is removably attached, it may be cleaned withvarious solvents without worrying about damaging the optic.

The preferred embodiment of the present invention has an upper surfacedefining a standard picatinny configuration including an elongate bodycarrying transverse block segments having the appropriate mil-specheight and grooves between the blocks or raised segments.

In a preferred embodiment, the side edges and bottom of the elongatebody are contoured. The bottom is specifically designed to match thecontour of the tangent-style sight base, preferably the AK rear sight'scontoured sidewalls which are pre-calculated to correspond to thetrajectory of the ammunition the rifle happens to be chambered for. Sothe sight sidewalls will differ for each rifle variation and the contouron the accessory mount of the present invention is going to basicallymatch the contour on the rear sight housing.

An important advantage of the present invention is that the accessorymount does not permanently alter the firearm in any way. It is just asimple matter of exchanging the standard rear sight lever arm for theprotuberance portion of the accessory mount. If a user has secondthoughts, he or she can go back and change it out the other way, sinceinstallation doesn't harm the firearm in any way.

The preferred material for making the accessory mount is steel,preferably 41 40 which is traditionally used because it is suitable foruse on a firearm. The accessory mount will preferably be finished usinga process called melonite which creates extremely hard surface in ablack finish, to allow for rough use, e.g., by professionals. Themelonite finish is made by a heat treating process that doesn't distortthe steel. Preferably, the method of making the Picatinny-style rails ofthe preferred embodiment uses wire EDM cutting to ensure absolutetrueness in conventional accuracy.

Laterally projected distally carried opposing pins engage the body ofthe sight and are spaced from the leading edge of the elongated body,and the forward or distal edge of the protuberance is shaped to engageand be bias against the rifle's powerful leaf spring. The accessorymount does not substantially move even in sustained automatic fire andso stays stable, doesn't get hot, doesn't change “zero” and won'trequire modification of the firearm.

The selected overall length of the picatinny style support surface forthe illustrated embodiment is 85 millimeters or approximately 3.346inches. Shorter lengths are possible, but longer lengths would probablypresent a slight concern, since the only attachment point to the firearmis in the front and the user relies upon a very powerful, very robustleaf spring to keep the accessory mount from wobbling, shaking orbouncing around. If an accessory mount of greater length were required,one can use a more forceful spring (with a higher spring coefficient Kfor the leaf spring) or, optionally, some set screws could be added, totighten and bear against the rifle's receiver as a rest against aperfectly stable surface.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)

The above and still further features and advantages of the presentinvention will become apparent upon consideration of the followingdetailed description of a specific embodiment thereof, particularly whentaken in conjunction with the accompanying drawings, in which:

FIG. 1 a shows, in elevation, the left side of an AK-47 rifle.

FIG. 1 b shows, in elevation, the right side of the AK-47 rifle of FIG.1 a.

FIG. 1 c shows, in perspective, the tangent rear sight the AK-47 rifleof FIGS. 1 a and 1 b.

FIG. 1 d shows, in perspective, the sight base of the tangent rear sightof FIG. 1 c, with the sight's leaf and slide removed from the base, inaccordance with the method of the present invention.

FIG. 2 shows a top view including the upper surface 16 of the accessorymount 10 in accordance with a preferred embodiment of the presentinvention;

FIG. 3 shows a right side view of the accessory mount 10 in accordancewith a preferred embodiment of the present invention;

FIG. 4 shows the distal or front end of the accessory mount 10 inaccordance with a preferred embodiment of the present invention;

FIG. 5 shows the tapered end 32 of the accessory mount 10 in accordancewith a preferred embodiment of the present invention;

FIG. 6 shows a top, angled view of the accessory mount 10 in accordancewith a preferred embodiment of the present invention;

FIG. 7 shows a bottom angled view of the accessory mount 10 inaccordance with a preferred embodiment of the present invention; and

FIG. 8 shows a bottom view including the lower surface 16 of theaccessory mount 10 in accordance with a preferred embodiment of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to FIGS. 1-8, FIGS. 1 a and 1 b show a standard AK-47rifle 100, and illustrate the position of the standard tangent rearsight assembly 102 including a pivoting elongated leaf member 104carrying a slide 106. As shown in FIG. 1 c, Tangent rear sight assembly102 includes a sight base 108 solidly mounted over the distal end of therifle's receiver 110, above the barrel 112. As best seen in FIG. 1 d,the standard sight base 108 has left and right spaced apart side walls113, 114 terminating distally in left and right opposing trunnion or pinreceiving segments 116 and 118. The open central portion 111 of sightbase 108 includes a powerful biasing leaf spring 120 which biasesupwardly to stabilize and retain the opposing pins or trunnions ofelongate rear sight leaf member 104, when installed. All of the forgoingis well known to gunsmiths and armorers around the world who build,repair and maintain the millions of AK-47 style rifles in use today.

FIGS. 2-8 illustrate different perspectives of a preferred embodiment ofthe accessory mount 10 of present invention, a unitary, one-pieceelongate support adapted to removably mount in place of pre-existingtangent or ladder-style sight slide or lever arm 104. Accessory mount 10is preferably fabricated or machined from a single piece of steel and isadapted for installation by a user without tools and without modifyingthe rifle or gunsmithing.

In accordance with the present invention, the accessory mount 10 has anelongated body 12 with a distally projecting protuberance 14 provided ata distal end of the elongated body 12. The elongated body 12 has anupper surface 16, lower surface 18, a right edge 20, and a left edge 22.The upper surface 12 is configured to accept accessories such as scoperings and preferably comprises a plurality of transverse raised segments24 alternately spaced with a plurality of transverse grooves 26configured to accept equipment or supports designed to clamp on aPicatinny-style rail providing a universal mounting surface for opticalsights. The distally projecting protuberance 14 has a right side 27carrying a right transversely projecting trunnion or pin 28 and a leftside 29 carrying a left transversely projecting trunnion or pin 30 onopposing sides of the distal protuberance 14. The right edge 20 and theleft edge 22 of the elongated body 12 are dimensioned to receiveclamping attachments and preferably have a V-shaped profile such thatthe center of the V-shape projects outwardly. Although a wide variety ofclamping attachments may be used in connection with the presentinvention, the reinforced firearm sight support ring disclosed in U.S.Pat. No. 6,629,381 can be affixed to the elongated body 12 including aPicatinny-style rail on its upper surface 16 as provided in a preferredembodiment of the present invention. Therefore, U.S. Pat. No. 6,629,381is expressly incorporated herein by reference.

The protuberance 14 is dimensioned to include a distal or forward endthat substantially fits within a pre-existing tangent-style sighthousing or base 108 and hinges within the sight housing's left and rightopposing trunnion or pin receiving segments 116 and 118 by releasablyengaging the mount's right and left pins 29, 30 leaving the elongatedbody 12 to project proximally from the sight housing's left and rightopposing trunnion or pin receiving segments 116 and 118. The elongatedbody 12 is not physically attached to the sight housing or rifle at anyother location other than the protuberance 14 via the right and leftpins 28, 30 and so mount 10 is hingedly engaged and supported in sighthousing or base 108.

Unlike other standard or mil-spec Picatinny-style rails that have asubstantial portion of the length of the rail physically attached to therifle (usually at two or more points along the rail's length), thepresent invention is attached to the rifle at a single point only, atthe mount's distal end, within the sight housing's at the protuberance14 via right and left pins 28, 30. This allows the accessory mount 10 ofthe present invention to be easily installed and removed from the riflewithout damaging or physically altering the rifle.

In a preferred embodiment of the present invention, the accessory mount10 has an overall length of about 105 mm or 4.134 inches and terminatesproximally in a tapered proximal or rear end 32. For most of its length,the mount's upper surface 16 has a preferred width of about 16.155 mmand the accessory mount preferably has opposing V-shaped lateral edges20, 22 that may extend about 2 mm each and are adapted to receiveclamping attachments used with either the preferred Picatinny or Weaver™style scope or accessory mounts. The distally projecting protuberance 14extends from a tapered segment (as seen in FIGS. 2, and 6-8) and has aprotuberance width that is preferably less than the width of theelongated body 12. In a preferred embodiment of the present invention,the protuberance width is 8 mm and the right pin 28 and left pin 30 eachextend laterally by 2 mm. The total height of the elongated body 12 ispreferably greater than the total height of the protuberance 14. Thetotal height of the elongated body 12 is preferably 9.32 mm and thetotal height of the protuberance 14 is preferably 3 mm. The exactdimensions of the accessory mount 10 may vary and the present inventionshould not be limited to the dimensions listed for the preferredembodiment. One of ordinary skill in the art will understand that thedimensions of the accessory mount 10 may vary without departing from thescope of the present invention.

A preferred embodiment of the present invention has an upper surface 16defining a standard mil-spec Picatinny configuration carrying transverseraised segments 24 having the appropriate mil-spec height alternatelyspaced with a plurality of transverse grooves 26 located between theraised segments 24. However, the present invention is not limited to anupper surface including a picatinny configuration. One of ordinary skillin the art will understand that the upper surface 16 may be configuredto include a variety of designs adapted for the accessory desired by theuser.

The lower surface 18, right side 20, and left side 22 of the elongatebody are contoured. The lower surface 18 is preferably designed to matchthe contour on the sidewalls of the pre-existing tangent-style sight. Ina preferred embodiment, the lower surface 18 is designed to match thecontour of an AK rear sight's contoured sidewalls which arepre-calculated to correspond to the trajectory of the ammunition therifle happens to be chambered for. Since the sight sidewalls will differfor each rifle variation, the contour on the lower surface 18 of theaccessory mount 10 of the present invention is going to preferably matchthe contour on the rear sight housing.

The accessory mount 10 is preferably made from a steel material, mostpreferably 4140 which is traditionally used in firearms. Accessory mount10 will preferably be finished using a process called melonite whichcreates extremely hard surface in a black finish, to allow for roughuse, e.g., by professionals. The melonite finish is made by a heattreating process that doesn't distort the steel. Preferably, the methodof making the upper surface 16 of the accessory mount 10 including theraised segments 24 and grooves 26 uses wire EDM cutting to ensureabsolute trueness and accuracy. However, the upper surface may bemachined using other appropriate methods known to those having skill inthe art.

The right pin 28 and left pin 30 located on the distal protuberance 14of the accessory mount 10 engage the sight base's left and rightopposing trunnion or pin receiving segments 116 and 118 and are spacedfrom the distal end of the elongated body 12. The distal protuberance 14is shaped to engage and be bias against the rifle's powerful sight leafspring 120. The applicant has discovered that accessory mount 10 willnot move significantly even during sustained automatic fire and so staysstable, doesn't get hot, doesn't change “zero” and won't requiremodification of the firearm.

The upper surface 16 of the elongated body 12 is preferably configuredas a Picatinny-style support surface having an overall length of about85 millimeters or approximately 3.346 inches. Shorter lengths arepossible, but longer lengths would probably present a slight concern,since the only attachment point to the firearm is distally, in thefront, and the user relies on the powerful, robust leaf spring 120 tokeep the accessory mount from wobbling, shaking or bouncing around. Ifan elongated body 12 of greater length were required, one can use a moreforceful spring (with a higher spring coefficient K for leaf spring 120)or, optionally, set screws could be added to tighten and bear againstthe rifle's receiver as a rest against a stable surface.

The accessory mount 10 is attached to the rifle at the pre-existingtangent-style sight housing or base 108. In a preferred method, the rearsight lever arm or leaf 104 is removed from the rear sight housing orbase 108. The accessory mount 10 is secured to the rifle by placing theprotuberance 14 within the rear sight housing such that the right pin 28and left pin 30 are positioned against the inner sidewalls 113, 114 ofthe sight housing. Since the protuberance 14 is biased against the rearsight leaf spring 120, the accessory mount 10 is stable and secured tothe rifle (e.g., 100). The present invention is intended to be used withany tangent-style or ladder-style sight (e.g., such as 102).

Although the accessory mount 10 may be adapted for attachment to anyrifle having a pre-existing tangent or ladder-style sight (e.g., such asa K98 Mauser, a Mosin-Nagant variant or one of the SKS family ofrifles), the AK family of rifles is of particular interest. As notedabove, the AK family includes the AK-47, the Chinese Norinco, or PolyTech, AKS, type 56, AK-47 S, the Hungarian AKM variations, the RomanianAKM variations, the AK-74, the Polish Tan-Tal and the Russian AK 74versions and the 545. Most often, three variations are discussed,including the AKS, AKM, and AK-74 and the pre-existing rear sightsupports differ only in minute details. Any reference herein to the AKfamily of weapons or the AK-47 is an express reference to the AK familyof weapons generally.

While this invention is well suited for retrofitting existing militarysurplus or service rifles (e.g., 100), it can also be incorporated as anOEM feature in rifles configured for sale or delivery with opticalsights.

Having described preferred embodiments of a new and improved method, itis believed that other modifications, variations and changes will besuggested to those skilled in the art in view of the teachings set forthherein. It is therefore to be understood that all such variations,modifications and changes are believed to fall within the scope of thepresent invention.

1. An accessory mount adapted for retrofitting on rifles usingtangent-style sights comprising: an elongated body having a distal endcarrying a distally projecting protuberance having a left side and anopposing right side; said left side of said protuberance carrying a lefttransversely projecting pin, and said opposing right side of saidprotuberance carrying a right transversely projecting pin; saidelongated body having a left edge and a right edge each dimensioned toreceive clamping attachments for firearm accessories; and said elongatedbody having an upper surface adapted to accept firearm accessories. 2.The accessory mount of claim 1, wherein said upper surface comprises aplurality of transverse raised segments alternately spaced with aplurality of transverse grooves.
 3. The accessory mount of claim 2,wherein said upper surface is Picatinny-style rail.
 4. The accessorymount of claim 1, wherein said right edge and said left edge of saidelongate body are dimensioned to have a V-shaped profile such that thecenter of the V-shape profile projects outwardly.
 5. The accessory mountof claim 1, wherein mount is a unitary, one-piece elongate member andsaid protuberance has a distal end dimensioned to engage the riflesight's left and right opposing pin receiving segments.
 6. The accessorymount of claim 1, wherein said elongated body has a width that isgreater than a width of said protuberance
 7. The accessory mount ofclaim 1, wherein said elongated body has a height that is greater than aheight of said protuberance.
 8. A method for retrofitting rifles havingtangent-style sights comprising: a) providing an accessory mountcomprising an elongated body having a distal end carrying a distallyprojecting protuberance having a left side and an opposing right side;said left side of said protuberance carrying a left transverselyprojecting pin, and said opposing right side of said protuberancecarrying a right transversely projecting pin; said elongated body havinga left edge and a right edge each dimensioned to receive clampingattachments; and said elongated body having an upper surface adapted toaccept accessories; b) providing a rifle including a sight housingcomprising opposing sidewalls and fitted with a leaf spring; and c)inserting said protuberance within the sight housing such that said leftpin and said right pin are secured against said opposing sidewalls ofthe sight housing and said protuberance is biased against the leafspring.
 9. The method of claim 8, wherein said elongated body remainsoutside of said sight housing.
 10. The method of claim 8, wherein saidaccessory mount is attached to said rifle only at said protuberance viasaid left and right pins.
 11. The method of claim 8, further comprisingd) attaching an accessory to said accessory mount.
 12. The method ofclaim 11, wherein said accessory is a scope attached to said accessorymount using a sight support ring.
 13. A rifle carrying a releasablyaffixed mounting rail, comprising: a) a tangent-style sight base sightbase with left and right spaced apart side walls terminating distally inleft and right opposing pin receiving segments and fitted with a biasingspring; b) an accessory mount comprising an elongated body having adistal end carrying a distally projecting protuberance having a leftside and an opposing right side; said left side of said protuberancecarrying a left transversely projecting pin, and said opposing rightside of said protuberance carrying a right transversely projecting pin;said elongated body having a left edge and a right edge each dimensionedto receive clamping attachments; and said elongated body having an uppersurface adapted to accept accessories; wherein said left pin and saidright pin of said protuberance are releasably secured in said sightbase's left and right opposing pin receiving segments and saidprotuberance is held against said spring.
 14. The rifle of claim 13,wherein said elongated body extends proximally beyond the proximal endof said sight base.
 15. The retrofitted rifle of claim 13, wherein saidaccessory mount is attached to said rifle only at said distallyprojecting protuberance via said left and right pins.